The need of butt-splicing together two lengths of optical fiber is widespread in various applications of optical fibers, e.g., in optical fiber communication systems. A variety of techniques for accomplishing such splicing have been developed. Among them are flame fusion splicing, laser fusion splicing, and arc fusion splicing. Especially the latter process has been substantially automated, and arc fusion splicers are commercially available.
Although splicing of silica-based optical fiber is now largely routine, there remains at least one shortcoming. In particular, the tensile strength of the splice is typically substantially less than the tensile strength of the as-drawn, polymer-coated fiber, the "pristine" strength of the fiber. Those skilled in the art will readily appreciate that in certain industrial applications of optical fibers (e.g., submarine optical fiber communication systems, sensors in oil well installations, smart skin structures) the need for high strength splices is urgent.
Substantial progress in the field of high strength splices has already been made. See, for instance, J. T. Krause et al., ECOC '93, Proceedings, Vol. 2, p. 449, (1993). However, there typically is still a considerable difference in average tensile strength between a batch of fibers spliced according to the prior art and a corresponding batch of pristine fiber. This application discloses a splicing technique that can yield fusion splices with average strength close to the average pristine strength.